Presses for terminating wires by crimping a terminal onto an end thereof, require the ability to apply a substantial amount of force during the actual crimping. Such presses therefore, employ flywheel eccentrics, cams or toggles to impart motion to the ram and provide sufficient force to effect the crimp. A typical example of a flywheel operated press is shown in U.S. Pat. No. 3,343,398 which issued Sept. 26, 1967 to Kerns. This type of press is necessarily large due to the use of a stored energy flywheel which itself must be massive. The flywheel press, while effective as a stand-alone machine, is not easily integrated into an automated machine for manufacturing wire harness products or the like. One reason for this is that in order to achieve a sufficiently long ram stroke, about three inches or so, to allow clearance for the operation of wire feed mechanisms when the press ram is fully retracted, the flywheel press must be inordinately large.
Toggle and cam operated presses, on the other hand can be made quite compact. An example of a typical toggle actuated press is shown in U.S. Pat. No. 3,141,197 which issued July 21, 1967 to Hahn. Hahn shows a wire terminating press having a toggle mechanism actuated by an air cylinder. Toggle mechanisms, however, tend to be limited to imparting a very short stroke to the ram. Therefore, when the ram is fully retracted, there is insufficient clearance for the wire handling mechanisms to pass under the ram. Similarly cam operated presses can also be made quite compact. An example of such a press is shown in U.S. Pat. Application Ser. No. 07/222654, filed on July 21, 1988 by Hatfield and assigned to the present assignee. Hatfield utilizes a cam which engages a follower attached to the end of the cam in such a way that as the cam is rotated, the ram is caused to move a distance equal to the lift function of the cam. But, here again, this mechanism imparts a relatively short stroke to the ram. One way to lengthen the stroke is by means of a high lift cam which is necessarily substantially larger and more massive. This of course defeats attempts to provide a compact device that will easily integrate into an automated machine.
What is needed is a ram actuating mechanism that permits sufficient ram stroke to provide clearance for wire handling mechanisms and yet is compact and easily integrated into an automated machine.